This invention relates to electrical connecting devices of the type comprising two parts which have a conductor-receiving bore means extending therethrough and which can be rotated relative to each other. The bores in the two parts are such that the opening through the device, which is defined by the bores, is constricted when the parts are rotated so that a high pressure electrical contact is established between the connecting device and the conductor. Connecting devices of this general class are shown, for example, in U.S. Pat. Nos. 2,336,175, 2,159,153, 1,989,861 and in United Kingdom specification 28,153 AD 1913, which has an accepted date of Nov. 12, 1914.
Connecting devices of the eccentric bore type have been proposed in numerous prior patent publications. However, connecting devices of this general type are not in wide-spread use at this time, possibly because of the complexity or manufacturing cost of these prior devices and/or the absence of a certification feature in them. The term "certification feature" is herein used with reference to a feature which ensures that a sound electrical connection has been made after the device has been applied to a conductor. The general principles of connecting devices of this eccentric bore type are, however, sound and highly attractive, particularly in view of the fact that a device of this type can be assembled to a conductor at a worksite without the need of a specialized installing tool. The instant invention is directed to the achievement of an improved eccentric bore type connecting device which can be manufactured at a modest cost and which can be easily applied to a conductor with the aid of a pair of conventional wrenches. The invention is further directed to the achievement of a device which has a self-contained certification feature such that a brief inspection of the device after installation will reveal whether or not a sound electrical connection has been achieved.
This invention relates generally to the use of eccentric bores in rotary members to establish an electrical termination with a standard electrical wire. The electrical termination is established by the action of rotational or torsional shearing forces in addition to transverse shearing forces to produce a cold weld between adjacent strands as well as between the wire and the terminal body itself. This invention is especially, although not exclusively, intended for use with stranded aluminum cable of the type used in the utility industry. The terminal body comprises a female part and a male part having a plug received within a counterbore in the male part. Bores in both the male and female parts are offset with respect to the axis of rotation. Retaining means secure the two body parts against axial forces during termination and interacting stops limit rotary travel.
Among the objects of this invention are the achievement of an improved electrical and mechanical termination for stranded wire. This invention achieves this object by subjecting the strands to rotational and transverse shear forces to more effectively abrade the surface and remove oxide films from the strands. Cold welds forming metal-to-metal contact between the individual strands result in a good electrical termination with the entire cable and not just between the terminal and the outer strands which are more subject to being severed by transverse shear forces.
Another object of the invention is to provide an improved eccentric bore type connecting device. A further object is to provide a device having a minimum number of parts which can be manufactured at a low cost. A further object is to provide a device which is supplied to the user in assembled form and which cannot be disassembled as a result of carelessness or ordinary handling. A further object is to provide a connecting device which can be installed on a cable by a technician without specialized training in a very short time.